The Branch has conducted extensive investigations on the descriptive epidemiology of primary intracranial neoplasms using data from population-based registries world-wide. Analytic studies were carried out to investigate the relationship between intracranial neoplasms and tumors occurring at other sites. These studies included careful review of tumor nomenclature, disease definitions, and survey strategies. A case-control study of glioblastoma multiforme is now being conducted.